Add support for the protocol relative URLs for resources.

grails-app/taglib/org/grails/plugin/resource/ResourceTagLib.groovy

@@ -40,7 +40,7 @@ class ResourceTagLib {
 
         }
     ]
-    
+
     static writeAttrs( attrs, output) {
         // Output any remaining user-specified attributes
         attrs.each { k, v ->
@@ -445,7 +445,7 @@ class ResourceTagLib {
     def stash = { attrs, body ->
         stashPageFragment(attrs.type, attrs.disposition, body())
     }
-    
+
     protected getModuleByName(name) {
         def module = grailsResourceProcessor.getModule(name)
         if (!module) {
@@ -485,7 +485,7 @@ class ResourceTagLib {
         def debugMode = grailsResourceProcessor.isDebugMode(request)
 
         for (r in module.resources) { 
-            if (!r.exists() && !r.actualUrl?.contains('://')) {
+            if (!r.exists() && !URLUtils.isGlobalAbsolute(r.actualUrl)) {
                 throw new IllegalArgumentException("Module [$name] depends on resource [${r.sourceUrl}] but the file cannot be found")
             }
             if (log.debugEnabled) {
@@ -525,7 +525,7 @@ class ResourceTagLib {
         }
         def ctxPath = request.contextPath
         def uri = attrs.remove('uri')
-        def abs = uri?.indexOf('://') >= 0
+        def abs = URLUtils.isGlobalAbsolute(uri)
 
         if (!uri || !abs) {
             if (uri) {
@@ -535,7 +535,7 @@ class ResourceTagLib {
                 // via g.resource
                 attrs.contextPath = ctxPath
                 uri = grailsLinkGenerator.resource(attrs)
-                abs = uri.contains('://') 
+                abs = URLUtils.isGlobalAbsolute(uri)
             }
         }
 
@@ -587,12 +587,13 @@ class ResourceTagLib {
         }
 
         // If the link has to support linkUrl for override, or fall back to the full requested url
-        // we resolve without query params, but must keep them for linking        
-        def linkUrl = res ? res.linkUrl : contextRelUri
+        // we resolve without query params, but must keep them for linking
+        def linkUrl = res ? res.linkUrl : reluri
 
-        if (linkUrl.contains('://')) {
+        def baseUrl = '' // @todo get from config
+        if (URLUtils.isGlobalAbsolute(linkUrl) || baseUrl) {
             // @todo do we need to toggle http/https here based on current request protocol?
-            return [uri:linkUrl, resource:res]
+            return [uri:baseUrl ? baseUrl+linkUrl : linkUrl, resource:res]
         } else {
             // Only apply static prefix if the resource actually has ResourceMeta created for it
             uri = res ? ctxPath+grailsResourceProcessor.staticUrlPrefix+linkUrl : ctxPath+linkUrl
@@ -635,7 +636,7 @@ class ResourceTagLib {
         def o = new StringBuilder()
         o << "<img src=\"${info.uri.encodeAsHTML()}\" "
         def attribs = res?.tagAttributes ? res.tagAttributes.clone() : [:]
-		def excludes = ['dir', 'uri', 'file', 'plugin']
+        def excludes = ['dir', 'uri', 'file', 'plugin']
         attribs += attrs.findAll { !(it.key in excludes) }
         attrs = attribs
 

src/groovy/org/grails/plugin/resource/ResourceMeta.groovy

@@ -141,7 +141,7 @@ class ResourceMeta {
     boolean isActualAbsolute() {
         actualUrl.indexOf(':/') > 0
     }
-    
+
     boolean isDirty() {
         !originalResource || 
         (originalResource.lastModified() != originalLastMod)
@@ -212,7 +212,7 @@ class ResourceMeta {
     // Hook for when preparation is starting
     void beginPrepare(grailsResourceProcessor) {
         def uri = this.sourceUrl
-        if (!uri.contains('://')) {
+        if (!URLUtils.isGlobalAbsolute(uri)) {
 
             // Delete whatever file may already be there
             processedFile?.delete()
@@ -347,7 +347,7 @@ class ResourceMeta {
             return null
         }
     }
-    
+
     String getActualUrlParent() {
         def lastSlash = actualUrl.lastIndexOf('/')
         if (lastSlash >= 0) {

src/groovy/org/grails/plugin/resource/ResourceModule.groovy

@@ -94,7 +94,7 @@ class ResourceModule {
     ResourceMeta newResourceFromArgs(Map args, svc, boolean singleResourceModule) {
         def url = args.remove('url')
         if (url) {
-            if (!url.contains('://') && !url.startsWith('/')) {
+            if (!URLUtils.isGlobalAbsolute(url) && !url.startsWith('/')) {
                 url = '/'+url
             }
         }

src/groovy/org/grails/plugin/resource/URLUtils.groovy

@@ -30,4 +30,13 @@ class URLUtils {
         !url.startsWith('#') && 
         !(url.indexOf('://') >= 0)
     }
+
+    /**
+     * Works out if url is globally absolute, as in it begins with a protocol
+     * like http:// or just //
+     */
+    static Boolean isGlobalAbsolute(url) {
+        url?.indexOf('://') >= 0 ||
+        url?.startsWith('//')
+    }
 }